"""Regenerate chunks.jsonl metadata without re-embedding (CPU-only, offline).

The dual-source retrieval work enriches each ``Chunk`` with structured
``metadata`` (IDA: sector/category/experience/measures; directive: article
title). That metadata is **not embedded**, so the vectors and chunk order are
unchanged — meaning the committed ``index.faiss`` stays byte-identical and we
only need to rewrite ``chunks.jsonl``.

This script loads the existing index + old chunks, rebuilds the corpus with the
new metadata, asserts the rebuilt chunks line up 1:1 with the live vectors
(same ids, same order, same count), then re-persists. No GPU, no embedding —
runs in well under a second.

Usage::

    uv run python scripts/refresh_metadata.py
"""

from __future__ import annotations

import sys
from pathlib import Path

# Allow running as a plain script (`python scripts/refresh_metadata.py`).
sys.path.insert(0, str(Path(__file__).resolve().parents[1]))

from src.backend.indexing.ingest import (  # noqa: E402
    build_corpus,
    load_directive_chunks,
    load_ida_chunks,
)
from src.backend.indexing.store import DEFAULT_INDEX_DIR, VectorStore  # noqa: E402


def main() -> None:
    store = VectorStore()
    if not store.load():
        raise SystemExit(
            f"No index at {DEFAULT_INDEX_DIR}. Build it first (scripts/build_index.py "
            "or scripts/build_index_modal.py) before refreshing metadata."
        )

    old_ids = [c.id for c in store._chunks]
    ntotal = store._index.ntotal

    n_dir = len(load_directive_chunks())
    n_ida = len(load_ida_chunks())
    new_chunks = build_corpus()
    new_ids = [c.id for c in new_chunks]

    # Alignment guard: the rebuilt chunks must line up exactly with the stored
    # vectors, else chunks.jsonl would point at the wrong embeddings.
    if len(new_chunks) != ntotal:
        raise SystemExit(
            f"Count mismatch: rebuilt {len(new_chunks)} chunks but index has "
            f"{ntotal} vectors. Re-embed (build_index) instead of refreshing."
        )
    if new_ids != old_ids:
        raise SystemExit(
            "Order/id mismatch between rebuilt chunks and the existing index. "
            "The corpus changed shape — re-embed (build_index) instead."
        )

    store._chunks = new_chunks
    store.persist()  # rewrites chunks.jsonl (+ identical index.faiss)

    n_meta = sum(1 for c in new_chunks if c.metadata)
    print(
        f"refreshed: directive={n_dir} ida={n_ida} total={len(new_chunks)} "
        f"ntotal={ntotal} with_metadata={n_meta} → {DEFAULT_INDEX_DIR}"
    )


if __name__ == "__main__":
    main()